RF Transmitter Having Broadband Impedance Matching for Multi-Band Application Support

ABSTRACT

Systems and methods are provided for a broadband, closed-loop RF transmitter for multi-band applications that employs a single RE path to service multiple bands of operation. Embodiments of the present disclosure implement a broadband impedance matching module, which avoids the need for several costly and complex narrow-band matching networks. In an embodiment, the broadband impedance matching module includes concentric, mutually coupled inductors. By adding this broadband impedance matching functionality, delay is significantly reduced because a single path can be used to service multiple bands.

FIELD OF THE INVENTION

This invention relates to radio frequency (RF) transmitters and morespecifically to multi-band RF transmitters.

BACKGROUND

Many conventional RF transmitters utilize a distinct RF path (i.e.,multiple modulators and RF amplifier lineups) for each supportedfrequency band. These multiple RF paths increase the cost of producingthe transmitter for each additional band that is supported. Further, theuse of distinct RF paths for each band increases the delay in aclosed-loop feedback RF transmitter, which can impair the stabilitymargin of the feedback system.

What is needed are methods and systems for efficiently providingmulti-band application support using an RF transmitter.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The accompanying drawings, which are incorporated in and constitute partof the specification, illustrate embodiments of the disclosure and,together with the general description given above and the detaileddescriptions of embodiments given below, serve to explain the principlesof the present disclosure.

FIG. 1A is a block diagram of a conventional transmitter.

FIG. 1B shows a block diagram of a conventional multi-band transmitter.

FIG. 2 is a block diagram of a transmitter integrated with a Cartesianfeedback loop.

FIG. 3A shows a block diagram of a multi-band transmitter with afeedback loop in accordance with embodiments of the present disclosure.

FIG. 3B shows block diagram of an embodiment of the present disclosureincorporating additional RF paths into the multi-band transmitter ofFIG. 3A.

FIG. 3C shows a block diagram of an embodiment of the present disclosurefor a multi-band transmitter with a Cartesian feedback loop that has asingle antenna supporting multiple bands.

FIG. 3D is a block diagram of a receiver including a broadband matchingmodule.

FIG. 4A is a circuit diagram of a broadband matching module that can beused in accordance with embodiments of the present disclosure.

FIG. 4B shows a circuit diagram of a matching module that includesexemplary values for the elements shown in FIG. 4A.

FIG. 5 is a diagram illustrating the mutual coupling of inductors inmatching module in accordance with embodiments of the presentdisclosure.

FIG. 6 is a flowchart of a method for transmission of a signal tomultiple RF paths within different frequency bands using a broadbandmatching module in accordance with embodiments of the present invention.

FIG. 7 is a flowchart of a method for receiving a plurality of signalswithin different frequency bands and forwarding them for processingusing a broadband matching module in accordance with embodiments of thepresent invention.

Features and advantages of the present invention will become moreapparent from the detailed description set forth below when taken inconjunction with the drawings, in which like reference charactersidentify corresponding elements throughout. In the drawings, likereference numbers generally indicate identical, functionally similar,and/or structurally similar elements. The drawing in which an elementfirst appears is indicated by the leftmost digit(s) in the correspondingreference number.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, numerous specific details are set forth toprovide a thorough understanding of the disclosure. However, it will beapparent to those skilled in the art that the disclosure, includingstructures, systems, and methods, may be practiced without thesespecific details. The description and representation herein are thecommon means used by those experienced or skilled in the art to mosteffectively convey the substance of their work to others skilled in theart. In other instances, well-known methods, procedures, components, andcircuitry have not been described in detail to avoid unnecessarilyobscuring aspects of the invention.

References in the specification to “one embodiment,” “an embodiment,”“an example embodiment,” etc., indicate that the embodiment describedmay include a particular feature, structure, or characteristic, butevery embodiment may not necessarily include the particular feature,structure, or characteristic. Moreover, such phrases are not necessarilyreferring to the same embodiment. Further, when a particular feature,structure, or characteristic is described in connection with anembodiment, it is submitted that it is within the knowledge of oneskilled in the art to affect such feature, structure, or characteristicin connection with other embodiments whether or not explicitlydescribed.

1. OVERVIEW

Because different frequency bands are used for communication indifferent parts of the world, support for many different frequency bandsis often necessary functionality to include when designing a wirelesstransmitter. Previous implementations of multi-band RF transmittersutilize a distinct RF path (i.e., multiple modulators and RF amplifierlineups) for each supported frequency band. Each of the multiple RFpaths in a conventional multi-band RF transmitter often includes anarrow band impedance matching network that is designed to provideimpedance matching between components for the particular narrow band ofinterest.

Because each added RF path in a conventional transmitter includesmultiple elements (e.g., modulators, RF amplifier lineups, andnarrow-band impedance matching modules), transmitter cost increases witheach additional supported frequency band. Further, the use of distinctRF paths for each supported frequency band increases the delay in aclosed-loop feedback RF transmitter, which can impair the stabilitymargin of the feedback system.

Embodiments of the present disclosure provide a broadband, closed-loopRF transmitter for multi-band applications that employs a single RF pathto service multiple frequency bands of operation. Thus, embodiments ofthe present disclosure can be used to provide a transmitter for a mobiledevice that works worldwide and includes a reduced amount of circuitry.By implementing a broadband impedance matching module, the RFtransmitter operates in a wide frequency bandwidth and can use a singlemodulator and/or demodulator to support multiple frequency bands. Thus,this wide operating frequency bandwidth reduces delay caused byimplementation of multiple modulators and demodulators. This reductionin delay enables a feedback loop to be coupled to the transmitter, whichimproves the linearity of the transmitter. Further, embodiments of thepresent disclosure include a compact, monolithic implementationcomprising concentric, mutually-coupled inductors, which avoids costlyand complex matching networks.

Thus, embodiments of the present disclosure avoid the need for multipleRF chains and enable multi-band application support and widelinearization of bandwidth due to a significant reduction in delayassociated with the broadbanding circuitry. Further, by enabling thesharing of hardware among multiple bands, embodiments of the presentdisclosure advantageously reduce the cost, power consumption, and diearea required to implement the closed-loop RF transmitter.

2. SYSTEMS 2.1 Conventional Multi-band Transmitters

FIG. 1A is a block diagram of conventional transmitter circuitry 100coupled to an antenna 114. Transmitter 100 in-phase (I) and quadrature(Q) inputs 101 that are filtered by respective low pass filters (LPF's)104. Transmitter 100 also includes an I/Q modulator 106 (e.g., a pair ofquadrature mixers 106 a and 106 b) supplied with a reference signal fromlocal oscillator (LO) 103 for performing up-conversion of the inputsignals 101. The output of I/Q modulator 106 is summed at the input ofnarrow- band impedance matching network 107, which includes one or morenarrow-band inductors. Narrow-band matching network 107 provides animpedance match between the output of I/Q modulator 106 and the rest ofthe RF path, including the pre-driver 108, power amplifier 110, andantenna 114. The narrow-band impedance matching network 107 maximizesthe power transferred by the RF path and minimizes signal reflections.

Because of the hardware limitations of narrow-band matching network 107,impedance matching is performed for a band-limited frequency range(e.g., the operating frequency of the coupled RF path). Becausepre-driver 108 and power amplifier 110 are narrow-band elements (i.e.,designed to operate for a specific frequency range), the hardwarelimitations of narrow-band matching network 107 do not substantiallyimpact the cost of producing the circuit when only one frequency band issupported. However, when multiple frequency bands are supported, thedesign of FIG. 1A becomes inefficient and expensive.

FIG. 1B is a block diagram of a conventional multi-band transmitter. Aspreviously discussed, pre-driver 108 and power amplifier 110 arenarrow-band elements that are designed to send a signal within apre-defined frequency band to antenna 114 for transmission. In FIG. 1B,additional transmitter components 112 are included to process a signalwithin a second frequency band and forward this signal to antenna 120for transmission. These additional transmitter components 112 include anadditional I/Q modulator 114, additional narrow-band matching network115, additional pre-driver 116, and additional power amplifier 118. If athird frequency range is to be supported using this transmitter design,a third set of transmitter components will be required.

These multiple RF paths increase the cost of producing the transmitterfor each additional frequency band that is supported. The RE paths inFIG. 1B cannot be designed to share a single narrow-band matchingnetwork because each coupled RF path operates in a different frequencyrange. Further, the RF paths in FIG. 1B cannot be designed to share asingle I/Q modulator because I/Q modulators 114 and 106 are couple tonarrow-band matching networks 115 and 107, respectively.

Embodiments of the present disclosure provide a broadband, closed-loopRF transmitter for multi-band applications that employs a single RF pathto service multiple bands of operation without adding significant delay.By using a single broadband matching module to support multiple RFpaths, embodiments of the present disclosure can provide a multi-bandtransmitter that requires less circuitry than the multi-band transmitterof FIG. 1B. For example, by broadbanding the matching network,embodiments of the present disclosure provide a transmitter that sharesa single matching network and I/Q modulator for each coupled RF path.

2.2 Transmitter With Feedback Loop and Narrow Band Matching Network

The transmitter design of FIGS. 1A and 1B also has additionaldisadvantages. For example, the use of distinct RF paths for each bandincreases the delay in a closed-loop feedback RF transmitter, which canimpair the stability margin of the feedback system. The additional delaycaused by the circuitry of FIG. 1B (e.g., introduced by requiringmultiple modulators 114 and 106) makes adding a feedback loopimpractical because feedback loops require a small delay to operateeffectively. FIG. 2 is a block diagram of a transmitter 100 integratedwith a Cartesian feedback loop. FIG. 2 shows a transmitter with a singleantenna 114 that transmits information within a single frequency band.Embodiments of the present disclosure with multiple frequency bands arediscussed below (e.g., with reference to FIG. 3). In FIG. 2, transmitter100 obtains inputs from two summing nodes 201 used to input informationfed back to transmitter 100 from the feedback loop. The feedback loopformed by feeding the outputs of I/Q demodulator 204 back intotransmitter 100 via summing nodes 201 enables transmitter 100 to operatein a very linear fashion (e.g., having a linear output signalamplitude). This increased linearity improves the performance oftransmitter 100. For example, by improving linearity in power sent totransmitter 114, more power can be sent to transmitter 114 withoutrequiring additional power consumption by the circuit of FIG. 2. Thus,even though additional components are added to transmitter 100 in FIG.2, the power consumption of the circuit of FIG. 2 can be lower than thepower consumption of the circuit of FIG. 1A because power linearity isimproved.

Coupler 200 is used to obtain a signal representative of the signal sentto antenna 114 and to forward this signal to a feedback loop forprocessing. For example, the feedback loop includes sensing receiver202, narrow band matching network 203, IQ modulator 204, and phaseshifter 206, all of which are described below. In an embodiment, coupler200 obtains a signal with a predetermined (e.g., predetermined based onthe hardware characteristics of coupler 200) fraction of the power thatis transmitted to antenna 114 and forwards this signal to the feedbackloop. Obtaining a signal with lower power reduces the power required foroperating elements within the feedback loop. The output of the feedbackloop can then be fed back into transmitter 100 (via summing nodes 201),which is designed to receive lower power inputs and to transmit a higherpower amplified output to antenna 114.

The output of coupler 200 is fed to sensing receiver 202, which measuresthe output power from the coupler. Since the coupler's output power canbe a predetermined (e.g., predetermined based on the hardwarecharacteristics of coupler 200) fraction of the power of the signal sentto antenna 114, sensing receiver 202 can determine the power of thesignal transmitted to antenna 114 based on the sensed power of thesignal received from coupler 200.

Sensing receiver 202 passes the signal to another narrow band matchingnetwork 203, which includes a narrow-band inductor. Because of thehardware limitations of the narrow-band inductor in narrow-band matchingnetwork 203, only frequencies within the range supported by narrow-bandmatching network 203 are supported. If signals from other frequencybands were received by sensing receiver 202, another narrow bandmatching network would be required to support narrow- band impedancematching for these received signals.

The output of narrow band matching network 203 is demodulated using I/Qdemodulator 204. Phase adjustment module 206 adjusts the phase of the LOsignal sent from LO 103 so that the same LO 103 can be used for I/Qmodulator 106 and I/Q demodulator 204. In other words, phase adjustmentmodule 206 adjusts the delay of the signal sent to I/Q demodulator 204so that its phase matches the phase of the signal sent to I/Q modulator106. The output of I/Q demodulator 204 is fed back into transmitter 100via the summing nodes 201.

While the embodiment of FIG. 2 includes a single I/Q modulator 106,additional I/Q modulators would be required if the embodiment of FIG. 2(using narrow-band impedance matching) were expanded to include supportfor another frequency range. For example, as shown in FIG. 1B, two I/Qmodulators (modulators 114 and 106) are needed for multi-bandapplication support if narrow-band impedance matching is used. If thefeedback loop of FIG. 2 were added to the multi- band transmitter ofFIG. 1B (incorporating narrow-band impedance matching), an additionalI/Q demodulator would also be required in the feedback path.

Adding an extra I/Q modulator/demodulator pair for each supportedfrequency band not only adds to circuit complexity but also introducesunwanted delay into the circuit. This delay prevents the feedback loopfrom operating effectively. Because embodiments of the presentdisclosure avoid the need for the addition of extra I/Qmodulator/demodulator pairs for every supported frequency band,embodiments of the present disclosure avoid unwanted delay and enablethe use of an effective Cartesian feedback loop, which enables thetransmitter to operate in a linear fashion and improves performance ofthe transmitter.

2.3 Multi-Band Transmitter With Feedback Loop and Broadband Matching

FIG. 3A shows a block diagram of a multi-band transmitter with afeedback loop in accordance with embodiments of the present disclosure.In FIG. 3A, broadband matching module 300 a is added to a transmitter302. In an embodiment, broadband matching module 300 a acts as awide-band transformer that interfaces between one set of quadraturemixers (e.g., I/Q modulator 106) and any number of pre-amplifiers andpower amplifiers. For example, conventional transmitters and theircorresponding narrow band impedance matching networks can operate in a200-300 MHz band. Broadband matching module 300 a can operate in a widefrequency range (e.g., in an embodiment, 2-4 GHz). This very wide bandfrequency range for matching enables broadband matching module 300 a tosupport a wide range of multiple RF paths. For example, in an embodimentbroadband matching module 300 a can be configured to support a 2-4 GHzrange so that a plurality of frequency bands can operate inside the 2-4GHz range. Other frequency ranges could be utilized as will beunderstood by those skilled in the arts.

Embodiments of the present disclosure including broadband matchingmodule 300 a enable additional RF paths to be coupled to a singlebroadband matching module. Broadband matching module 300 a enables theseadditional RF paths to utilize fewer components with respect to thoserequired by conventional RF transmitters. For example, the additional RFpath added to the conventional transmitter of FIG. 1B requiresadditional I/Q modulator 114 and additional narrow- band matchingnetwork 115. In the embodiment of the present disclosure illustrated byFIG. 3, the addition of broadband matching module 300 a avoids the needfor this additional modulator 114 and additional narrow-band matchingnetwork 115. Rather, in FIG. 3A, the additional components 304 added tosupport this additional RF path include additional pre-driver 306 andadditional power amplifier 308. Because I/Q modulator 106 is coupled toa broadband matching module 300 a, modulator 106 can perform inmodulation over a broad range of frequencies, including the operatingfrequency ranges used by power amplifiers 308 and 110. Thus, i theembodiment of FIG. 3A, separate modulators are not required for eachsupported frequency band because, when broadband impedance matching isused, modulation for a broad range of frequencies can be performed by asingle modulator without losing information when the signal is passed tothe broadband matching module.

In FIG. 3A, power amplifier 308 outputs a signal to antenna 312, whichis configured for operation in a different frequency band than thefrequency band used by antenna 114. Coupler 310 and coupler 200 obtainsignals representative of the signals sent to antennas 312 and 114,respectively, and transmit these signals to multiplexer 314. Multiplexer314 multiplexes these signals and sends them to sensing receiver 202,which senses the power of the multiplexed signal.

Since the output power of couplers 310 and 200 can be a predetermined(e.g., predetermined based on the hardware characteristics of couplers310 and 200) fraction of the power of the signal sent to antennas 114and 312, sensing receiver 202 can determine the power of the signalstransmitted to antennas 114 and 312 based on the sensed power of themultiplexed signal.

Elements 314, 202, 300 b, and 204 of FIG. 3A act as a multi-bandreceiver. Sensing receiver 202 transmits the signal to another broadbandmatching module 300 b, which interfaces to demodulator 204. In anembodiment, broadband matching module 300 b can be identical tobroadband matching module 300 a. The configuration of the elements ofbroadband matching modules 300 a and 300 b is explained in greaterdetail below with reference to FIG. 4A.

The use of broadband matching module 300 b in the feedback path alsoreduces the circuitry needed to add functionality to support additionalbands. For example, demodulation for multiple frequency bands can bedone using one I/Q demodulator 204 if broadband matching module 300 b isincluded in the circuit. Because broadband matching module 300 b canperform impedance matching for a wide range (e.g., in an embodiment, a2-4 GHz range) of signals received by sensing receiver 202, broadbandmatching module 300 b avoids the need to include multiple narrow-bandmatching networks for receiving signals within different frequencyranges.

Thus, by employing broadband matching, (N-1) transmit-side narrow-bandmatching networks, (N-1) I/Q modulators, (N-1) I/Q demodulators, and(N-1) receive-side narrow-band matching networks are eliminated, where Nis the number of bands served. Further, by avoiding the need to includethese additional I/Q modulators 114 and additional narrow-band matchingnetworks 115, delay within the circuit is reduced, which enables thelinearization provided by the Cartesian feedback loop.

FIG. 3B shows block diagram of an embodiment of the present disclosureincorporating additional RF paths into the multi-band transmitter ofFIG. 3A. Broadband matching module 300 coupled to each of these RF pathsavoids the need for additional I/Q modulators and additional narrow-bandmatching networks in each of these RF paths. For example, the additionalcomponents 314 added for the RF path added to FIG. 3B include pre-driver316 and power amplifier 318. The output of power amplifier 318 is inputto antenna 322. Coupler 320 obtains a signal representative of thesignal sent to antenna 322 and feeds this signal to multiplexer 314. Itshould be understood that any number of additional RF paths can becoupled to broadband matching module 300 in accordance with embodimentsof the present disclosure.

FIG. 3C shows a block diagram of an embodiment of the present disclosurefor a multi-band transmitter with a Cartesian feedback loop that has asingle antenna receiving data for transmission. In FIG. 3C, broadbandmatching module 300 supports circuitry for multiple frequency bands. Forexample, in FIG. 3C, pre-driver 108 and power amplifier 110 provide afirst RF path to support a first frequency band, pre-driver 306 andpower amplifier 308 provide a second RF path to support a secondfrequency band, and pre-driver 316 and power amplifier 318 provide athird RF path to support a third frequency band. If only one of thesefrequency bands is used for a transmission at any given time, multipleantennas are not required. Thus, in FIG. 3C, the outputs of poweramplifiers 318, 308, and 110 are multiplexed by multiplexer 324 and aretransmitted to a single antenna 326. The use of a single antenna asshown by FIG. 3C further reduces the circuitry required for themulti-band transmitter.

FIG. 3D shows a block diagram of a receiver including a broadbandmatching module in accordance with embodiments of the present invention.In FIG. 3D, an input signal 328 is passed to a sensing receiver 202.Impedance matching is performed by broadband matching module 300 b, andthe signal is demodulated by demodulator 204. The demodulated signal isthen forwarded for further processing 330. Because broadband matchingmodule 300 b can perform impedance matching for a wide range (e.g., 2-4GHz) of signals received by sensing receiver 202, broadband matchingmodule 300 b avoids the need to include multiple narrow-band matchingnetworks for receiving signals within different frequency ranges.Further, because impedance matching can be done over a wide range offrequencies when broadband matching module 300 b is incorporated intothe circuit, demodulation can be performed using a single demodulator204 for all supported frequency ranges.

2.4 Broadband Matching Module

FIG. 4A is a circuit diagram of a broadband matching module 300 that canbe used in accordance with embodiments of the present disclosure. Forexample, broadband matching module 300 can correspond to broadbandmatching modules 300 a and 300 b in FIGS. 3A, 3B, 3C, and 3D. Broadbandmatching module 300 performs an impedence match between portions of acircuit with differing impedences. The circuit portion having a lowerimpedance is coupled to the left side of the broadband matching module300 shown in FIG. 4A (i.e., it is coupled to capacitors 404 and 406).Capacitor CY 402 and resistor RY 400 represent the capacitance andresistance, respectively, that is experienced by broadband matchingmodule when the lower impedance circuit portion is coupled to broadbandmatching module 300. Likewise, the circuit portion having a higherimpedance is coupled to the right side of the broadband matching module300 shown in FIG. 4A (i.e., it is coupled to inductor L2 410). CapacitorCX 416 and resistor RX 416 represent the capacitance and resistance,respectively, that is experienced by broadband matching module when thehigher impedance circuit portion is coupled to broadband matching module300.

For example, broadband matching module 300 a in FIG. 3A performsimpedance matching between I/Q modulator 106 and pre-drivers 108 and306. Because I/Q modulator 106 has a higher impedance than pre-drivers106 and 306, I/Q modulator 106 is coupled to inductor L2 410. In FIG.4A, resistor RX 418 and capacitor CX 416 represent the resistance andcapacitance, respectively, that is experienced by broadband matchingmodule 300 a when it is coupled to I/Q modulator 106. Likewise, becausepredrivers 108 and 306 have a lower impedance than I/Q modulator 106,pre-drivers 108 and 306 are coupled to capacitors 404 and 406 shown inFIG. 4A. Resistor RY 400 and capacitor CY 402 represent the resistanceand capacitance, respectively, that is experienced by broadband matchingmodule 300 a when it is coupled to pre-drivers 108 and 306.

Broadband matching module 300 b in FIG. 3A performs impedance matchingbetween I/Q demodulator 204 and sensing receiver 202. Because I/Qdemodulator 204 has a higher impedance than sensing receiver 202, I/Qdemodulator 204 is coupled to inductor L2 shown in FIG. 4A. Resistor RX418 and capacitor CX 420 represent the resistance and capacitance,respectively, that is experienced by broadband matching module 300 bwhen it is coupled to I/Q demodulator 204. Likewise, because sensingreceiver 202 has a lower impedance than I/Q demodulator 204, sensingreceiver 202 is coupled to inductor capacitors 303 and 406 shown in FIG.4A. Resistor RY 400 and capacitor CY 400 represent the resistance andcapacitance, respectively, that is experienced by broadband matchingmodule 300 b when it is coupled to sensing receiver 202.

Broadband matching module 300 includes mutually coupled inductors thatenable broadband impedance matching to support coupled RF paths.Inductor 408 and capacitors 404 and 406 are sufficient for a narrow bandmatch. However, for broadband impedance matching, inductor L2 410 isadded (shown as elements 410 a and 410 b in FIG. 4A) and is mutuallycoupled 414 to inductor L1 408. Because of at least (1) the mutualcoupling 414 of inductor L2 410 to inductor L1 408, and (2) theinductance ratio between broadband matching module 300 can supportbroadband impedance matching for coupled RF paths. In one embodiment,the inductance ratio between inductor L1 408 and inductor L2 410 isapproximately 3:2 inductance ratio. However, other ratios could be used,as will be understood by those skilled in art.

FIG. 4B shows a circuit diagram of a broadband matching module thatincludes exemplary values for the elements shown in FIG. 4A. A broadbandmatching module with the values shown in FIG. 4B is operable to matchfrequencies in 2 GHz to 4 GHz bands. Other values can be selected, aswill be understood by those skilled in the art. By selecting differentcomponent values for the circuit elements shown in FIG. 4B, thebroadband matching module 300 of FIG. 4B can be configured to operate inanother wide frequency band. For example, if a plurality of circuitelements that operate in a plurality of different frequency bands (e.g.,pre-drivers 108 and 306) is coupled to broadband matching module 300,values for the elements of broadband matching module 300 b (e.g., valuesfor capacitors 404 and 406 and inductors 408 and 410) can be selected sothat broadband matching module 300 is configured to operate in a widefrequency band that encompasses the plurality of different frequencybands of the elements it is coupled to.

Nodes 420, 422, 424, and 426 shown in FIGS. 4A and 4B represent ports atwhich circuitry of broadband matching module 300 couples to the inductornetwork formed by inductor L1 408 and inductor L2 410. These topology ofthis inductor network will now be explained in greater detail withreference to FIG. 5. The mutual coupling 414 of inductor L2 410 toinductor L1 408 is also shown in greater detail with reference to FIG.5.

2.5 Mutual Coupling in Broadband Matching Module

FIG. 5 is a diagram illustrating the mutual coupling 414 of inductors L1408 and L2 410 in broadband matching module 300 in accordance withembodiments of the present disclosure. FIG. 5 shows concentric,mutually-coupled, monolithic inductors in broadband matching module 300positioned as an inter-stage match. In other words, FIG. 5 showsinductor L2 410 as being positioned inside inductor L1 408. Element 500in FIG. 5 denotes the physical connection (e.g., via electrical wiring)between inductors L1 408 and L2 410, which is shown in FIG. 4A as nodes422 and 424. Inductor L1 408 couples to inductor L2 410 at primarypositive port 422 and primary negative port 424. Capacitors 404 and 406(shown in FIG. 4A) also couple to primary positive port 422 and primarynegative port 424. High impedance circuit portions that are to bematched are coupled to inductor L2 410 at secondary positive port 420and secondary negative port 426. Element 502 in FIG. 5 represents thecentral portion of inductor L1 408. Thus, when current travels from node422 to node 424 (shown in FIG. 4A), current travels from primarypositive port 422, through central portion 502 of inductor L1 408, andproceeds to primary negative port 424.

In an embodiment, inductors L1 408 and L2 410 comprise a plurality ofmetal traces disposed on a semiconductor substrate. The “coupling” of L2410 to itself 414 b is caused by the turning inside inductor L2 410. Inother words, the proximity between any two or more concentric metaltraces of inductor L2 410 causes a coupling between the traces,resulting in L2 412 being “coupled” to itself and represented bycoupling 414 b. Further, L1 408 is “mutually coupled” 414 to L2 410because L2 410 is located in an interior, open region of L1 408. Thepositioning of inductor L2 410 inside inductor L1 408 causes additionaltransfer of energy between L2 408 and L1 410, causing these inductors tobe mutually coupled.

For example, when inductors are positioned next to each other, a changein current in one inductor induces a voltage in the other inductor,causing the inductors to become mutually coupled. The configuration ofinductors L1 408 and L2 410 shown in FIG. 5 b, in which inductor L2 410is positioned within the the interior region defined by the traces ofinductor L1 408, enables a greater amount of coupling than theconventional coupling caused when inductors are positioned next to eachother because each outer portion of the traces of inductor L2 410 ispositioned “next to” a portion of the metal traces of inductor L1 408.This concentric arrangement of inductors L1 408 and L2 410 enablesimproves energy transfer between inductors L1 408 and L2 410 and reducesthe amount of energy reflected when the energy is transferred. Becausereflected energy is reduced, inductors L1 408 and L2 410 can be used tocreate an impedance matching network that operates for a broad range offrequencies (e.g., in an embodiment, 2 GHz to 4 GHz).

In one embodiment, the spacing between the metal traces of L2 410 issmaller than the spacing between L2 410 and L1 408. This smaller spacingcauses a higher coupling coefficient M22 414 b when compared to thecoupling coefficient M12 414 a caused by the mutual coupling between L1408 and L2 410. This coupling configuration improves the ability ofbroadband matching module 300 to perform broadband impedance matching sothat a larger range of RF paths can be supported.

2.6 Implementation

Embodiments of the present disclosure are applicable to various types ofRF transmitter feedback systems, including systems with both feedbackand non-feedback transmitters. For example, embodiments of the presentdisclosure can apply to polar feedback systems and Cartesian feedbacksystems. Further, embodiments of the present disclosure are applicablein 3G, 4G, and WiMAX systems.

Embodiments of the present disclosure shown in FIGS. 1A-5 can be locatedon a single integrated circuit (IC) or on a plurality of integratedcircuits. For example, in an embodiment, circuitry for each supportedfrequency band can be located on a different integrated circuit. In anembodiment, all circuitry (e.g., all circuitry shown in FIG. 3C) islocated on a single integrated circuit.

3. METHODS

FIG. 6 is a flowchart of a method for transmission of a signal tomultiple RF paths having different frequency bands using a broadbandmatching module in accordance with embodiments of the presentdisclosure. In step 600, a transmit signal is modulated with a broadbandmodulator (e.g., using I/Q modulator 106). In step 602, impedancematching is performed using a broadband impedance matching module. Forexample, broadband matching module 300 a performs broadband impedancematching for a wide band of frequency ranges to support a plurality ofRF paths having different frequency ranges. In step 604, the signal isamplified using a plurality of amplifiers (e.g., amplifiers 318, 308,and 110). Because broadband matching module 300 a performs broadbandimpedance matching for a wide band of frequency ranges, a singlematching network can be used to support multiple RF paths.

FIG. 7 is a flowchart of a method for receiving a plurality of signalswithin different frequency bands and forwarding them for processingusing a broadband matching module in accordance with embodiments of thepresent disclosure. In step 700, a plurality of RF signals withindistinct frequency bands are received (e.g., by sensing receiver 202. Instep 702, impedance matching is performed using a broadband matchingmodule operable over a plurality of frequency bands. For example,broadband matching module 300 b performs wideband impedance matching forall of the received signals. In step 704, the RF signals are demodulatedusing a broadband demodulator operable over a plurality of frequencybands (e.g., using I/Q demodulator 204). Using a broadband matchingmodule to perform impedance matching for a plurality of signals withindifferent frequency bands avoids the need for multiple narrow-bandmatching networks.

4. Conclusion

It is to be appreciated that the Detailed Description section, and notthe Abstract section, is intended to be used to interpret the claims.The Abstract section may set forth one or more but not all exemplaryembodiments of the present invention as contemplated by the inventor(s),and thus, is not intended to limit the present invention and theappended claims in any way.

The present invention has been described above with the aid offunctional building blocks illustrating the implementation of specifiedfunctions and relationships thereof. 1 he boundaries of these functionalbuilding blocks have been arbitrarily defined herein for the convenienceof the description. Alternate boundaries can be defined so long as thespecified functions and relationships thereof are appropriatelyperformed.

The foregoing description of the specific embodiments will so fullyreveal the general nature of the invention that others can, by applyingknowledge within the skill of the art, readily modify and/or adapt forvarious applications such specific embodiments, without undueexperimentation, without departing from the general concept of thepresent invention. Therefore, such adaptations and modifications areintended to be within the meaning and range of equivalents of thedisclosed embodiments, based on the teaching and guidance presentedherein. It is to be understood that the phraseology or terminologyherein is for the purpose of description and not of limitation, suchthat the terminology or phraseology of the present specification is tobe interpreted by the skilled artisan in light of the teachings andguidance.

The above systems and methods may be implemented as a computer programexecuting on a machine, as a computer program product, or as a tangibleand/or non- transitory computer-readable medium having storedinstructions. For example, the functions described herein could beembodied by computer program instructions that are executed by acomputer processor or any one of the hardware devices listed above. Thecomputer program instructions cause the processor to perform the signalprocessing functions described herein. The computer program instructions(e.g. software) can be stored in a tangible non-transitory computerusable medium, computer program medium, or any storage medium that canbe accessed by a computer or processor. Such media include a memorydevice such as a RAM or ROM, or other type of computer storage mediumsuch as a computer disk or CD ROM. Accordingly, any tangiblenon-transitory computer storage medium having computer program code thatcause a processor to perform the signal processing functions describedherein are within the scope and spirit of the present invention.

While various embodiments of the present invention have been describedabove, it should be understood that they have been presented by way ofexample only, and not limitation, it will be apparent to persons skilledin the relevant art that various changes in form and detail can be madetherein without departing from the spirit and scope of the invention.Thus, the breadth and scope of the present invention Should not belimited by any of the above-described exemplary embodiments, but shouldbe defined only in accordance with the following claims and theirequivalents.

What is claimed is:
 1. A multi-band transmitter, comprising: amodulator; a broadband matching module coupled to an output of themodulator, wherein the broadband matching module is configured toperform impedance matching over a broadband frequency range; a firstamplifier coupled to an output of the broadband matching module, whereinthe first amplifier is configured to amplify signals within a firstfrequency range, and wherein the first frequency range is within thebroadband frequency range; and a second amplifier coupled to an outputof the broadband matching module, wherein the second amplifier isconfigured to amplify signals within a second frequency range, andwherein the second frequency range is within the broadband frequencyrange.
 2. The multi-band transmitter of claim 1, wherein the broadbandmatching module comprises: a first inductor; and a second inductormutually coupled to the first inductor.
 3. The multi-band transmitter ofclaim 1, wherein the broadband matching module comprises: a first,inductor including a first plurality of concentric metal traces; and asecond inductor including a second plurality of concentric metal tracespositioned within an interior region defined by the first plurality oftraces of the first inductor.
 4. The multi-band transmitter of claim 3,wherein the broadband matching module further comprises: a firstcapacitor coupled to the first inductor; and a second capacitor coupledto the first inductor.
 5. The multi-band transmitter of claim 1, furthercomprising: a first coupler coupled to an output of the first amplifier;a second coupler coupled to an output of the first amplifier; and asensing receiver configured to receive signals from the first couplerand the second coupler.
 6. The multi-band transmitter of claim 5,further comprising: a second broadband matching module coupled to anoutput of the sensing receiver, wherein the second broadband matchingmodule is configured to perform impedance matching over the broadbandfrequency range.
 7. The multi-band transmitter of claim 6, furthercomprising: a demodulator coupled to: an output of the second broadbandmatching module, and an input of the modulator.
 8. The multi-bandtransmitter of claim 7, further comprising: a phase adjustment modulecoupled to the output of the second broadband matching module and to alocal oscillator, wherein the phase adjustment module is configured tomatch a first phase of the demodulator to a second phase of themodulator.
 9. The multi-band transmitter of claim 1, wherein themodulator is a quadrature modulator.
 10. The multi-band transmitter ofclaim 1, wherein the first amplifier is coupled to a first antennaconfigured to transmit signals within the first frequency range, andwherein the second amplifier is coupled to a second antenna configuredto transmit signals within the second frequency range.
 11. Themulti-band transmitter of claim 1, wherein the first amplifier and thesecond amplifier are coupled to a shared antenna configure to transmitsignals within the broadband frequency range.
 12. A multi-band receiver,comprising: a receiver configured to: receive a first signal within afirst frequency range, and receive a second signal within a secondfrequency range; a broadband matching module coupled to an output of thereceiver, wherein the broadband matching module is configured to performimpedance matching over a broadband frequency range including the firstfrequency range and the second frequency range; and a demodulatorcoupled to an output of the broadband matching module.
 13. Themulti-band receiver of claim 12, wherein the broadband matching modulecomprises: a first inductor; and a second inductor mutually coupled tothe first inductor.
 14. The multi-band receiver of claim 12, wherein thebroadband matching module comprises: a first inductor including aplurality of concentric metal traces; and a second inductor including asecond plurality of concentric metal traces positioned within aninterior region defined by the first plurality of traces of the firstinductor.
 15. The multi-band receiver of claim 14, wherein the broadbandmatching module farther comprises: a first capacitor coupled to thefirst inductor; and a second capacitor coupled to the first inductor.16. A method comprising: modulating a transmit signal with a broadbandmodulator operable over a plurality of frequency bands; performingimpedance matching using a broadband matching module operable over aplurality of frequency bands; and distributing the transmit signal to afirst amplifier operable in a first frequency band and a secondamplifier operable in a second frequency band.
 17. The method of claim15, further comprising: receiving a plurality of signals, wherein atleast two signals in the plurality of RF signals are within distinctfrequency bands; performing impedance matching using a broadbandmatching module operable over a plurality of frequency bands; anddemodulating the RF signals using a broadband demodulator.
 18. Themethod of claim 16, wherein the broadband matching module is operableover a frequency band including the first frequency band and the secondfrequency band.
 19. The method of claim 16, wherein the broadbandmatching module performs the impedance matching using a first inductor asecond inductor mutually coupled to the first inductor.
 20. The methodof claim 16, wherein the broadband matching module performs theimpedance matching using a first inductor including a first plurality ofconcentric metal traces and a second inductor including a secondplurality of concentric metal traces positioned within an interiorregion defined by the first plurality of traces of the first inductor.